The present invention relates to photosensitive materials employing microencapsulated photosensitive compositions and, more particularly, to materials in which the photoinitiator also functions as the image-forming agent.
Imaging materials which employ microencapsulated photosensitive compositions are known. U.S. Pat. Nos. 4,399,209 and 4,440,846 to the Mead Corporation describe imaging materials in which images are formed by exposure controlled release of an image-forming agent from a microcapsule containing a photocurable composition. The image-forming agent is a substantially colorless compound which forms a colored image or mark when it contacts a developer material. In U.S. Pat. No. 4,440,846, the developer is on the same sheet as the microcapsules. In U.S. Pat. No. 4,399,209, it is on a separate sheet.
U.S. Pat. No. 3,219,446 to Berman discloses an imaging system which, like the Mead systems, employs a microencapsulated photocurable composition, however, unlike Mead's systems, Berman's system uses a colored dye. The release of the dye from the microcapsules is disclosed as being controlled by exposure of the photocurable composition. The dye is differentially transferred to plain paper where the image is formed.
U.S. Pat. No. 3,579,399 to Chang et al. discloses an imaging material in which the photosensitive layer is a dispersion of microdroplets of a photohardenable composition containing a color coupler in a binder. Exposure renders the droplets impermeable to a photographic developer which is applied later and which reacts with the color coupler in the unexposed droplets to produce a color image. Chang et al. describe a full color, panchromatic imaging material in which the photocurable compositions are sensitized by initiator dyes which are bleached upon exposure. The color coupler image is controlled by the polymerization initiated by the bleached dye.